[time-nuts] Are there any company selling refurbished/reconditioned Cesium tubes?

Bob kb8tq kb8tq at n1k.org
Sun Jun 30 21:09:07 UTC 2019


Hi

Based on several replacements on a “high performance” 5071 …. 6 to 7 years of 24/7/365 seems to
be about the point things start to get flakey. Maybe not dead, but crazy enough that it lets you know 
it needs a new tube ( = ADEV is not even close to what it should be ..).

Cost several years back for the swap out was right at $40K. The process included hazmat shipping 
silly nonsense. That part delayed the process by almost 2 months. 

Bob

> On Jun 30, 2019, at 4:55 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
> 
> I'm pretty sure you can still buy a new Cs tube for a hp 5071A. But the price is several tens of thousands. I've not found anyone selling replacement tubes for all the older Cs standards. Treat it like a ballpoint pen. It will end some day and you can't refill it. Worse, you can't really tell how much "ink" is left in the tube. Still, it's easy to swap in a new or used tube if you have it.
> 
> On eBay stay away from Cs standards with the "high performance" option. Yes, these tubes give you ~2x better stability -- but at the cost of ~4x the beam current and thus maybe a quarter of the lifetime. I haven't seen any recent data but you can roughly expect a high-performance tube to last 7 to 10 years if used full-time and if there are no other defects. A standard tube might last 20 to 25 years if used full-time and there are no other defects.
> 
> So it's not as bad as you think. And I would never use the word "disappointing". Come on, decades of physics research, not to mention a few Nobel prizes, turned a room-sized atomic physics laboratory into a compact 19" unit that fits on your desk. And its portable.
> 
> The more you study the history of timekeeping and the more you learn about how cesium standards work the more you will be absolutely amazed at what it is that you own. Treat it with great awe and respect. Like others have said, you don't have to run it 24x7 and if its working well today, it could easily outlast you. Now that's the disappointing part...
> 
> /tvb
> 
> 
> On 6/29/2019 7:46 AM, Taka Kamiya via time-nuts wrote:
>> I paid very little to purchase, so it's not a big deal from financial stand point, but it's disappointing that once it's done, it's done.
>> By recommendation, I am keeping it mostly off and turn it on few days earlier of anticipated use, mostly to calibrate/verify something else.  My usual reference is GPSDO and Rubidium which are redundant and always on.
>> 
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> I'm stuck in a wormhole....  Hello, worms!
>> 
>>     On Friday, June 28, 2019, 5:00:25 PM EDT, Taka Kamiya via time-nuts <time-nuts at lists.febo.com> wrote:
>>    I have a Datum FTS 4040A.  I believe the tube is original but it is still locking and staying in lock just fine.  I don't know for how long.  In an event where tube goes soft/dead, replacing it with factory new replacement part is out of question for cost.  Are there any refurbished tubes available from anyone?
>> 
>> ---------------------------------------
>> (Mr.) Taka Kamiya
>> I'm stuck in a wormhole....  Hello, worms!
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> 
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